Method for producing bands of aluminum.



UNITED STATES PATENT OFFICE;

ERWIN RICHARD LAUBER AND ROBERT VICTOR I Q'EHER, OF EMMIS'HOFEN, I

SWITZERLAND.

METHOD FOR PRODUCING BANDS 01E ALUMTNUM.

1,178,863. No IJrawing.

To all whom it may concern:

Be it known that we, ERWIN RICHARD LAUBER, a subject of the Emperor ofGermany, and ROBERT VIoToRNnHER, a cltizen of Switzerland, both residingat Emmishofen, Switzerland, haveinvented certain new and usefulImprovements in .Methods for Producing. Bands of Aluminum; and we dohereby declare the following to be a full, clear, and exact descriptionof the invention, such as will enable others skilled in the art to whichit appertains to make and use the same.

Methods have been proposed by which small sheets or foils of aluminum of0.0003 inch in thickness can be produced, but strips or hands ofaluminum could only be rolled at a minimum thickness of 0.0008 inch, andonly a yard or two in length. Bands of a less thickness heretofore havebecome plaited or torn during the rolling process so that.

they could not be rolled to lengthsdesired by the trade.

According to our invention, aluminum, after being annealed by I 320 C.and then allowed to cool, is drawn by rolls at a high tensile strain andunder a comparativel small pressure. ingly bands 0 aluminum of athickness less than 0.0008 inch, as for-instance 0.0003 inch, can beproduced, which becomes neither plaited nor torn, and may be produced amile, more or less inlen th."

When producing only one ban according to our method, a thick band orstrip of aluminum, after having been heated to 270 to 320 C. to annealthe same is wound onto a roll, and the band passed from the latter whilebeing braked between two rollsdriven in opposite directions and at asmall pressure, the band becoming elongated thereby. The strip isconsequently subjected simultaneously toa rolling and drawing action.

The material can best be elongated when annealed at the above mentionedtempera ture, as it then possesses the highest available tensilestrength. As the material retains this strength when becoming coldagain, but loses it by mechanical treatment, a repeated annealing of thematerial at the above mentioned temperature becomes necessary from timeto time. 1 This annealing Specification of Letters Patent.

heating to 270 to- Accord- Patented Apr. 11, 1916.

Application filed September 21, 1911. Serial No. 650,505.

may be performed at suitable intervals during the treatment of thematerial. As a consequence the aluminum band can be sub- Jected to sohigh a tensile strain that it is not only elongated, but is also broughtin v a smooth condition to the rolls.

Oil is suitably introduced between the metal and rolls during thedrawing operation, and as the surfaces "of the rolls become smoothedthereby the polishing of the rolls is rendered unnecessary as inprocesses heretofore practised. Any good lubricating oil 1s used, such,for example, as motor oil, automobile oil and the like; For renderingthe material smooth and ductile, the strip or band when rolled to lessthan 0.0008 of an mob in thickness is annealed in the presence of air. i

Hitherto separate thin strips or bands of i only limited length could beproduced simultaneously on account ofthe lubricant employed such as alayer of oil, petroleum,

soapy water or the like, which was intro duced between the layers ofmetal to prevent them from becoming stuck together. Exper ments haveproven that these fluids can be applied as separating layers foralumlnum foil of only about 0.0008 inch thickness or more. Strips orbands of less thickness become perforated like a sieve, by theemployment of these lubricants, and by reason of thegranulation of themetal due to the elongation beforeit enters the rolls. The separatingfluid by its hydrostatic pressure then breaks through the weak parts ofthe band. A layer of lubricant, as oil, which adheres to the materialfrom a preceding elongation exerts the same unfavorable act1on.Experiments have proven that the perforation by lubricant which adheresto the material from the preceding rolling beginls with a thickness ofthe foil of 0.0006 inc By our method bands consisting of several layersof aluminum may'be produced band at the last period of rolling butbefore being folded into two bands and wound up,

is rolled with a mixture consisting of a-' small amount of lubricant, asoil and a volatile solvent, as benzin, petroleum, turpentine or similarmaterials. So small an amount of fluid is applied that only a very thinlayer of this limpid liquid and slightly adhering mixture covers thefoil, when leaving the rolls. Thus a sticking of the two layers to'eachother is prevented, and, on the other hand the layer of lubricant is toothin to perforate the foil. The same result can be obtained byintroducing between the strips or bands, vapor, for instance steam,vapor of oil, alcohol, ether or benzm, so that the bands, when passingthe rolls are separated from each other. by a very thin and welldistributed layer. Thus for 1nstance, the aluminum band before beingrolled two-fold is freed from the oil adhering to it from the precedingrolling. This may be done by evaporating the oil, or by washing with asolvent, as benzin. Afterward, a tube provided with a large number offine openings is placed between the bands at the side where they enterthe rolls. The tube which may be electrically heated is supplied withthe fluid to be evaporated, alcohol or ether for instance, and a finelayer of vapor, which exerts no hydrostatic pressure, is formed therebybetween the alumlnum bands entering the rolls.

A verythin uniformly distributed, separating layermay also be obtainedin the following manner: Bands still of so great a thickness, (0,0008inch or more) thatthey are not perforated by the heavier lubricantintroduced between them, are freed from their coating of lubricant oroiland wound up. An easily evaporating fluid 1s introduced between thelayers before or as they enter the rolls. The bands after passing therolls are wound up tight and the woundup bands, with the separatinglayers between the single bands, are heated so that the surplus ofseparating fluid is evaporated'and the remaining part ofsaid fluid inthe form of vapor is equally distributed between the bands where it iscondensed to a very fine separating layer. The bands separated in thismanner may be rolled and drawn to 0.00025 inch, as has been proven byexperiments. These bands neither stick to each other nor becomeperforated. By rollingseveral superposed bands at the same time theproduct is increased, as compared with rolling single bands, moreoverthe product consisting of several bands stands the Working processbetter than single bands.

I We believe that we are the first to produce aluminum foil of less thantwo onehundredths (.02) of a millimeter in thickness (0.0008 inch), andin fact we have exceeded all expectations and have produced singlestrips of aluminum foil six and eight one-thousandths of a millimeter(0.0002

in the form of a band while under tensile strain and under a smallpressure, the band becoming elongated thereby to a thickness less than0.0008 inch, substantially as described.

2; The method of producing aluminum foil in the form of bands, whichcomprises annealing sheet aluminum at a temperature of from 270 to 320C., rolling the aluminum in form of a band under a high tensile strainand under small pressure and lubricating the surfaces of the aluminum.

3. The method of producing aluminum foil in form of bands, whichcomprises lubricating the surfaces of several superposed aluminum foilsby very fine and well distributed layers of lubricating fluid to preventthe sticking of the foils to each other, repeatedly elongating the foilswhile under high tensile strain by a slight rolling pressure to athickness of less than 0.0008 inch, and annealing the aluminum atintervals of the rolling operation, substantially as described.

i. The method of producing aluminum foils in band form, whichcomprises-simultaneously elongating several superposed aluminum foilswhile said foils are under high tensile strain but under small pressureto a thickness of less than 0.0008 inch, lubricating the surfaces of thefoils by the condensable vapor of a suitable lubricant beforeelongation, and annealing the aluminum at intervals of elongatingoperations, substantially as set forth.

5. The method of producing aluminum foils in form of bands, whichcomprises lubricating the surfaces of superposed strips of aluminum,removing the excess of lubricant by vaporization, repeatedly subjectingthe superposed strips to a rolling operation at a slight pressure whilethe strips are under tension to a thickness less than 0.0008 inch,.a-ndannealing the bands at intervals during the rolling operation,substantially as described.

6. The method of producing aluminum foils in band form, which comprisesannealing the aluminum at a temperature of 270 to 320 C., rollingsuperposed bands of aluminum under a high tensile strain and un' der asmall pressure while lubricating the surfaces of the aluminum, freeingthe bands from excess of lubricant, coating the surfaces of the aluminumwith a very thin,

well distributed layer of lubricant to prevent the foils from stickingtogether, and repeatedly elongating the foils under high tensile strainand slight pressure to a thickness below 0.0008 inch, substantially asdescribed.

7. The method of producing aluminum foil, which comprises annealing thealuminum at a temperature of 270 to 320 C., rolling the aluminum insuperposed bands under high tensile strain and slight pressure whilelubricating the aluminum surfaces, freeing the bands from lubricant andthen lubricating the surfaces of the bands at subsequent rollingoperations with very fine well distributed layers of a fluid to preventthe bands from sticking together, and repeatedly elongating the bandsunder high tensile strain and slight pressure to a thickness less than0.0008 inch, substantially as described.

8. The method of producing aluminum foil, which comprises annealing thealuminum at a temperature of 270 to 320 0., rolling the aluminum intobands while lubricating its surfaces and while under high tensile strainand slight pressure, removing the lubricant from the rolled bands,superposing and rolling the resulting bands while under tensile strainand pressure and during such rolling providing the surfaces of the bandswith a thin lubricant well distributed to prevent the sticking togetherof the bands, and repeating the rolling under strain and pressure untilthe thickness of the bands is less than 0.0008 inch, substantially asdescribed.

9. The method of making very thin and long aluminum strips, whichcomprises repeatedly rolling the annealed aluminum while under tensilestrain and slight pressure, then rolling several annealed layers of theresulting foil while under tension and slight pressure, lubricating thesurfaces of the layers with a thin lubricant, and continuing the rollingoperations underhigh tension and slight pressure until the strips areless than 0.0008 inch in thickness, and periodically annealing the metalbetween some of the rolling operations.

10. The method of making very thin strips of aluminum foil, whichcomprises repeatedly rolling a thick strip of annealed aluminum whileunder tension until thin, then lubricating the surfaces with a thinlubricant and continuing the rolling operations under tension andpressure, and annealing at intervals of the rolling operations.

11. The method of making very thin and long aluminum foil, whichcomprises repeatedly rolling thin lubricated strips While under tensilestrain and slight pressure, and annealing the strips at intervals of therolling operations.

In testimony that we claim the foregoing as our invention, we havesigned our names in presence of two subscribing witnesses.

ERWIN RICHARD LAUBER. ROBERT VICTOR NEHER.

Witnesses ERNST FISCHER, CARL CUBLpR.

